Sisson Pond Reservoir Report
Nearby: St Marys Pond Lawton Valley Reservoir
Last Updated: December 17, 2025
Sisson Pond, located in Portsmouth, Rhode Island, is a local government-owned water supply reservoir with a primary purpose of providing water to the community.
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Summary
The dam, completed in 1900, is a rockfill structure standing at a height of 14 feet and has a storage capacity of 550 acre-feet. The pond covers an area of 90 acres and is fed by Lawton Valley Brook, with a maximum discharge capacity of 355 cubic feet per second.
Despite its important role in supplying water to the area, Sisson Pond has been assessed as having a high hazard potential and poor condition. The last inspection in 2013 revealed the need for improvement and maintenance. The dam is under state regulation, with permitting, inspection, and enforcement procedures in place to ensure public safety and water resource sustainability. The local community, along with state regulatory agencies, must work together to address the dam's condition and mitigate potential risks associated with its operation.
As water resources and climate enthusiasts, it is crucial to recognize the significance of maintaining infrastructure like Sisson Pond to ensure the safety and reliability of our water supply systems. By staying informed about the condition of dams and reservoirs in our area, we can advocate for necessary upgrades, repairs, and risk management measures to protect our communities and the environment. Sisson Pond serves as a reminder of the importance of proactive management and investment in our water resources for a sustainable future.
Year Completed |
1900 |
Dam Length |
1150 |
Dam Height |
14 |
River Or Stream |
LAWTON VALLEY BROOK |
Primary Dam Type |
Rockfill |
Surface Area |
90 |
Hydraulic Height |
12 |
Nid Storage |
550 |
Structural Height |
14 |
Hazard Potential |
High |
Nid Height |
14 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Sisson Pond
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